11-22-02 17:39
No 382438
Procedure(from Rhodiums site)=100 grams of safrole was placed in a 250 ml RB flask fitted with a water-cooled Allihn reflux condenser, and was heated with good stirring. When the solution started to boil, 1 gram of KOH pellets was added through the condenser, and the safrole immediately took on a brown color. Next, 15 grams of CaO was also added through the condenser, and the solution was allowed to reflux for 15 minutes, and the heat was turned off, and the solution was poured into a beaker and was allowed to cool. The dark brown suspension was vacuum filtered through a pad of celite, and the filter cake was washed with 2x50 ml of CH2Cl2. The CH2Cl2 was removed through distillation at atmospherical pressure, and unreacted safrole was also distilled off at 240°C (bath temperature), and amounted to about 1 ml. The residue was distilled at aspirator vacuum (~25 mmHg), and the isosafrole came over at 120-130°C as a water-white oil, weighing 70 grams (70%).
Experimental:
135grams of distilled safrole was added to a 500mL RB flask attached to a condensor, on a peanut-oil bath and heated until the safrole started to boil at approx ~240C. Then 1.5g of KOH flakes were added. Then 15grams of CaO was added to the safrole and was let to reflux for 15minutes. (just as the procedure calls for). There was some H2O in the safrole but it kept on boiling off and condensing and when it hit the hot oil it made a scary "explosion" on the hot oil surface. Anyway it was left to reflux for 15minutes and then the heat was turned off.
The flask was cooled and it was brownish in color and the CaOH2 formed was black with white specks. It was left to settle and the isosafrole/safrole was poured off. The residue was washed with ethanol and saved. The CaOH/KOH residue in the flask was dissolved with HCl.
The resulting liquid came over at 133-135C and was suspected isosafrole but my H2O boils over at 33C under vacuum leading me to believe that this was just safrole. Under my vacuum isosafrole is supposedly to come over at 150C. I got nothing to come over at that temp.
In the procedure it said their isosafrole came over at 120-130C @25mm HG. From Chromics distillation safrole html, it would mean that isosafrole would come over at 140C under 25mmHG. Was the procedure true? That looks like safrole and not isosafrole.
----------------------------------------
Is there any tests i can do to see if this truely is isosafrole?? Or any other way to purify isosafrole by freezing?
Thanks!
Sink or SWIM
(Hive Bee)
11-22-02 17:53
No 382441
At around 20mmHg using an asiprator vacuum, I get safrole to distill at around 115-120DegC. After isomerisation is complete, the liquid comes over at 130-145DegC using same pump and vacuum.
So I know its isosafrole and then proceed with next step without any concerns.
So isn't the easiest thing to do, find out what your safrole distills over at using the same pump and compare.
Abacus
(Hive Addict)
11-22-02 18:00
No 382446
swim had this problem, combined with a pump that was too strong. Just do an ATM with a small amount, that way, theres no questions. Real fast and easy- swim just followed goiters advise, he put a bit (5mls or so) in a test tube and just heated a pot of oil over the stove. Doesnt take long at all, but bee careful if your gonna do it that way, you know- fire tends to make things really hot some times
.Im not the bearded man upstairs, Im a bald guy with a healthy penis. So open yer pie-hole!
(Hive Bee)
11-22-02 18:11
No 382449
Its not just that, the procedures are bugging me! What is correct Chromics BP chart or the procedure??
Yeah ill try the atmospheric GOD,
thanks
Sink or SWIM
(Chief Bee)
11-22-02 19:31
No 382469
../rhodium /safrole
(Hive Bee)
11-22-02 22:20
No 382498
What do you mean the procedures are bugging you? surely you don't give a crap about the procedures, its the RESULT of having isosafrole that is important.
Also, if you want to know a very easy iso procedure with no hassles search my posts for an answer. This reaction is so foolproof its funny.
Abacus
(Hive Bee)
11-22-02 22:39
No 382503
Many here are confused about the boiling points of substances distilled under vacuum. The confusion is caused by the following factors:
Methodical:
Inaccurate vacuum gauges
Improper thermometer readings
Vacuum leakage
Mathematical:
Differing elevation above sea level
The fact that the nomograph to calculate boiling points under vacuum cannot be referenced like a simple ratio, as it is a hyperbolic function, and exponential factors influence the equation.
You will have to determine at what temperature the substance boils using your particular equipment and method at your particular elevation above sea level and then apply this number to the nomograph to devise an equation that reflects accurately the ratio between the reduced pressure boiling point and the recorded atm boiling point.
Pr(+)tium
(Hive Bee)
11-23-02 08:57
No 382610
Nah it wasnt that. The procedure that was on Rhodiums site under isomerization html, for KOH/CaO says that their own isosafrole came over under 25mm Hg @120-130C but at 25mm HG its suppose to come over at 140C. I think that procedure needs clarification.
So far my vacuum measurments are on the dot with water boiling at 33C and safrole coming over at 133-135C. I guess that isomerization failed. I believe i used CaOH2 instead of CaO.
Sink or SWIM
(Hive Addict)
11-23-02 09:36
No 382620
SWIM sees two possible issues Cloud-ster:
1. SWIS is using a different type of thermometer which can
make it's readings different (SWIM's tried an oven
thermometer - spring type, and a candy thermometer -
mercury type), and gotten two different readings 10
degrees apart!)
2. SWIS is reading a different type of oil then the
original experimentor.
3. there was water in SWIS oil to start with, SWIM's read
that that'll seriously fuck with things, even though
SWIS said that it came out during the reflux, SWIM would
have boiled it off ahead of time...SWIM figures SWIS has
almost got it, try again.
* disclaimer, keep in mind, SWIM's never actually done it
with KOH and CaO, but from what SWIM's read, it should
bee pretty straight forward...SWIM wishes it had some KOH
flakes :( it's bee-n forced to buy large quantities of
the stuff :(, and SWIM's broke :(
It tastes like burning!
(Hive Bee)
11-23-02 10:23
No 382627
I use a digital thermometer accurate to 0.1C and up to 200C. Water boils @1 ATM at 98.9C (i live in a slightly higher altitude) I believe this thermometer is very accurate.
OH well, isomerizations sometimes fail, and its because of the water.. :(
Sink or SWIM
(Newbee)
11-23-02 12:13
No 382635
If you where at 1 ATM the water would be boiling at 100°C, so your thermometer would be reading 99.9 threw 100.1. But, it's not so your barometric pressure is some where around 31.02 inches of Hg or 1.02 ATM. You can use http://www.biggreenegg.com/boilingPoint.
Sorry for the anal-retentive post, but the statement "Water boils @1 ATM at 98.9C (i live in a slightly higher altitude)" bothers me.
Edit: errmm...2 Of course when I correct some one, I mess up in the math and drop an operator. Those numbers should be 0.96 ATM and 28.82 in of Hg.
(Hive Bee)
11-23-02 15:15
No 382670
The above post is incorrect!
For example water boils at 50-70C on some mountains!
I live at an altitude slightly higher than sea-level therefore the atmosphere is slightly less dense where swim lives than at sea-level!
The higher the atmosphere pressure the higher the boiling point, and the lower the pressure the lower the boiling point (such as under vacuum)
DUH!!!
Sink or SWIM
(Hive Bee)
11-23-02 15:24
No 382672
Abacus,
SWIM is trying your "easy iso". Hopefully this will be swims best way of isomerizing if all goes well!
Thanks again,
Sink or SWIM
(Title on BackOrder)
11-24-02 19:52
No 383041
Isomerization with KOH/CaO is about the easiest reaction you will perform. If you're having trouble with this, then you might want to do some more reading. As far as your boiling point goes, you can't really confirm you have isosafrole or safrole under vacuum if you don't know how much vacuum you are pulling. Just take a few mls of your questionable liquid and perform a boiling point test at atmospheric pressure to determine what you have.
If at first you don't succeed, try, try again. Then give up. There's no use being a fool about it.
(Hive Bee)
11-25-02 13:30
No 383270
I did the CaO/KOH and NaOH isomerizations and it still comes over at 133C leading me to believe even after these isomerizations its still safrole??? What are the chances that it is stills safrole? I think it was sucessfully isomerized the first time and i will plug it into the oxone rxn to see if it has!
Sink or SWIM
(Hive Bee)
11-25-02 16:15
No 383323
SWIDR has done numerous KOH vacuum isomerizations. Funny thing is, at ATM iso boils from 240-250 C (H2O boils at 100 C, and safrole at 230-234 C). SWIDR knows that the cis isomer boils somewhat lower than trans and that longer reaction times favor trans formation, but iso never boils >250 C. WHAT GIVES? Also, all oxidation attempts have yielded not-ketone which is somewhat less viscous and boils about 10 C more than MDP-2-P should (164 C @25mm HG instead of around 155 C). This no-ketone does not aminate (all successful dreams dreamt via wacker). SWIDR would think this is glycol d/t higher BP, but glycol should be MORE viscous, right?!
TRISMUS!!!
(Hive Addict)
11-25-02 16:52
No 383331
you can also try freezing it for another semi-quick test.
Im not the bearded man upstairs, Im a bald guy with a healthy penis. So open yer pie-hole!
(Title on BackOrder)
11-25-02 23:15
No 383414
Are you sure you have calcium oxide and not calcium hydroxide? If this is the case, then you could not be getting enough water out of the reaction.
What reaction are you using to oxidize your supposed iso?
If at first you don't succeed, try, try again. Then give up. There's no use being a fool about it.
(Hive Bee)
11-26-02 06:48
No 383522
Does anyone have thoughts for SWIDR's last post? Has anyone never been able to get iso to distill at >250 C?! Also, The Isomerization of Safrole: A Review on Rhodium's site citing boiling iso at 120-130 @25mm Hg (Isomerization with KOH/CaO) is wrong indeed. At 25mm Hg the B.P. of trans-iso should be 137.5 C. (The cis-iso might boil in the upper end of that range though.)
TRISMUS!!!
(Hive Addict)
11-26-02 17:53
No 383755
and hope it doesn't freeze?
It tastes like burning!
(Hive Addict)
11-26-02 18:02
No 383759
If you suspect that isomerisation was a failure, and the quickest way to do this is by taking an atm bp-, if it boils @ safroles bp, then chill and add a seed crystal (of safrole). If it isnt below -15 or whatever the melting point of iso, you may bee able to actually freeze out a good portion of unreacted safrole. I just offered this suggestion as another alternative for verifying what was left after an isomerisation. Swim managed to separate un-isomerised safrole from a botched oxone run this way, he had vac distilled, but got one solid fraction going from safroles bp up to ketones bp for his too strong of a pump (this was before he learned to slow it down, and use a vigreux)
Im not the bearded man upstairs, Im a bald guy with a healthy penis. So open yer pie-hole!
(Hive Addict)
11-26-02 18:35
No 383770
SWIM thanks you.
It tastes like burning!
(Hive Bee)
11-26-02 18:46
No 383776
Inspection of swims supposed CaO was indeed Ca(OH)2. Upon reaction with water no heat was given off. Ca(OH)2 needs to be heated with a blow torch to turn into CaO.
Unfortunatley swims homemade alcohol burner doesnt cut it.
Sink or SWIM
(Hive Bee)
11-27-02 10:04
No 383937
Swim did an atomospheric bp of sassafras oil and suspected isosafrole. Both came over at ~230C
What the *&^! is up with my isomerization process? I did the KOH/CaO (which failed because it was Ca(OH)2. I also did at atomospheric isomerization using 5% NaOH. Arragh!!
Time to go the chem store and buy REAL CaO....
Sink or SWIM
(Hive Addict)
11-27-02 11:31
No 383960
this is the easiest method i've seen... Post 278285 (RoundBottom: "Re: vacuum refluxing", Chemistry Discourse), it's not rocket science, people.
Now with 12% more Bottom!
Nymphomania is not a disease, its a goal! (Methadist)
(Hive Bee)
12-02-02 06:26
No 385496
Does anyone have thoughts for SWIDR's last post? Has anyone never been able to get iso to distill at >250 C?! Also, The Isomerization of Safrole: A Review on Rhodium's page citing boiling iso at 120-130 @25mm Hg (Isomerization with KOH/CaO) is wrong indeed. At 25mm Hg the B.P. of trans-iso should be 137.5 C. (The cis-iso might boil in the upper end of that range though.)
TRISMUS!!!
(Chief Bee)
12-02-02 14:34
No 385627
(Rated as: excellent)
Has anyone never been able to get iso to distill at >250°C?!
Oh yes, certainly! If you let the reaction go on for a while, any formed iso will convert to the trans form.
Here's all the physical data published on Isosafrole in Beilstein:
5-cis-propenyl-benzo[1,3]dioxole (cis-isosafrole)
mp -21.5°C1
bp 77-79°C/3.5mmHg1
5-trans-propenyl-benzo[1,3]dioxole (trans-isosafrole)
mp 6.6°C2
mp 8.2°C1
bp 86-86°C/3.4mmHg1
1: Bull.Soc.Chim.Fr. 1053-1056 (1957)
2: Z. Phys.Chem. <A> 167; 407-419 (1934)
Isosafrole, cis/trans unspecified
252.4-252.7°C/768mmHg - Chem.Ber.; 42; 1909; 3080.
252°C/760mmHg - Ann. Soc. scient. Bruxelles; 48; 1928; 122.
253.5°C/735.4, 179.5°C/100, 135.6°C/20 and 120.2°C/10mmHg - Rechenberg,C.; Einfache und fraktionierte Destillation, 2. Aufl. <Miltitz 1923>, S. 300.
120°C/15mmHg - Acta Pol.Pharm.; 17; 1960; 241,242; Chem.Abstr.; 55; 14351; 1961.
125-127°C/16mmHg - J.Amer.Chem.Soc.; 47; 1925; 1149.
127-128°C/15mmHg - J.Prakt.Chem.; <2> 115; 1927; 332.
131°C/17mmHg - Bull.Soc.Chim.Fr.; 1964; 1892. (../rhodium/pdf /benzodioxole
112-116°C/12mmHg - Ann.Chim.(Rome); 52; 1962; 1261,1263.
123°C/11.5mmHg - Chem.Ber.; 42; 1909; 3080.
116-117°C/9mmHg
111-112°C/6mmHg - Rocz.Chem.; 39; 1965; 1251,1255; Chem.Abstr.; 64; 12656.
Isosafrole, selected syntheses
Synth.Commun. 23(10), 1379-1384 (1993) - Safrole isomerization, KOH/Aliquat 336 (5%), 5min @ 80°C
J.Chem.Soc.Perkin Trans.1 2307-2326 (1985) - Erythro Horner-Wittig, NaH/DMF, 30min @ 50°C, 85% trans-iso, 4% cis-isosafrole
Tetrahedron Lett. 24(36), 3931-3934 (1983) - Erythro Horner-Wittig, NaH/DMF, 60min @ 50°C, 84% cis-isosafrole
J.Chem.Soc.Perkin Trans.1, 19, 2393-2397 (2001) - Post 385717 (Rhodium: "Isosafrole via Wittig Olefination of Piperonal", Novel Discourse)
J.Pharm.Sci. 81(12), 1219-1222 (1992) - Post 431447 (FriendlyFinger: "Safrole Isomerising methods", Methods Discourse) Safrole Isomerization (KOH/n-BuOH, 3h @ RT, 98% trans-isosafrole)
Tet. Lett. 27(22), 2529-2532 (1986) - Allylbromide/5-Bromobenzodioxole/PdCl2(d
Synthesis 701-703 (1983) - beta-MeS-3,4-MD-styrene/MeMgI, PPh3/NiCl2, Benzene/Ether, 68%
J Braz Chem Soc 11(4), 371-374 (2000) - Post 431447 (FriendlyFinger: "Safrole Isomerising methods", Methods Discourse) Safrole Isomerization (KOH/n-BuOH, 3h @ reflux, 95% yield)
(Hive Bee)
12-02-02 16:03
No 385655
Thanks for the info!
A good way to check for sucessful isomerization if you are unsure about the boiling points of safrole/isosafrole is to add 20mL of sassafras oil to the isomerized oil and distill together. This way you will see the boiling point of safrole first, then after ~20mL later it will shoot 10-15C higher and then collect your isosafrole as you will know the correct temperature. This worked for SWIM ;)
Sink or SWIM
(Hive Bee)
12-03-02 06:26
No 385804
Thanks for the references Rhod!!!
hidden CLOUD said "it will shoot 10-15C higher", referring to iso- boiling point compared to safole. This would mean 244-249 C, since safrole's B.P. is 234 C. Well, SWIDR's safrole boils at 230-234 C, and iso- boils at exactly 16 C higher (246-250 C). This has been repeated multiple times with the exact same results. SWIDR has never been able to get iso- to boil >250 C, nor has SWIDR seen the broad temp range that Rhod's Isomerization Review referred to ("the trans isomer boils at approx 10°C higher than the cis, so the isosafrole isomers are usually collected as a mixture over a temperature range"). SWIDR would expect that isomerizations have been successful, however is still stumped by what not-ketone really is (slightly lighter in color, less viscous, boils 5-10 C higher than ketone, and does not aminate). Parameters were as per buffered performic (scaled up to 3 mol) and oxone (scaled up to 1 mol) oxidations from Rhod's web page.
TRISMUS!!!